Ionic liquid-induced ultrathin and uniform N-doped carbon-wrapped T-Nb2O5 microsphere anode for high-performance lithium-ion battery

• Published in: Rare metals Vol. 40; no. 11; pp. 3205 - 3214
• Main Authors: Sun, Rui-Xue, Yue, Yang, Cheng, Xin-Feng, Zhang, Ke, Jin, Su-Ying, Liu, Guang-Yin, Fan, Yu-Xin, Bao, Yan, Liu, Xiao-Di
• Format: Journal Article
• Language: English
• Published: Beijing Nonferrous Metals Society of China 01.11.2021; Springer Nature B.V
• Subjects: Anodes; Biomaterials; Carbon; Chemistry and Materials Science; Diffusion rate; Electrical resistivity; Electrode materials; Energy; Heat treatment; Ionic liquids; Lithium; Lithium-ion batteries; Materials Engineering; Materials Science; Metallic Materials; Microspheres; Nanoscale Science and Technology; Niobium oxides; Original Article; Orthorhombic phase; Physical Chemistry; Rechargeable batteries; Ultrathin N-doped carbon; Lithium-ion battery; T-Nb; Full cell; Ionic liquid; O
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-020-01681-1

Orthorhombic-phase Nb 2 O 5 (T-Nb 2 O 5 ) has been widely investigated as an intercalation anode material for Li-ion batteries due to the larger interplanar lattice spacing and high safety. However, its applications are limited by the intrinsic low electric conductivity. Herein, an ultrathin N-doped carbon-coating layer was constructed on porous T-Nb 2 O 5 microspheres uniformly via a convenient thermal treatment method with ionic liquid as a carbon precursor. The synthesized T-Nb 2 O 5 @N–C exhibits significantly enhanced rate capability (155.5 mAh·g –1 at 20C) than initial T-Nb 2 O 5 (110.2 mAh·g –1 at 20C). Besides, T-Nb 2 O 5 @N–C shows ultralong cycle life, with only a 0.02% decrease in the capacity per cycle at a high current density of 10C. The corresponding electrochemical tests show that the preferable rate capability of T-Nb 2 O 5 @N–C electrode is attributed to the increased electronic conductivity and pseudocapacitance contribution induced by ultrathin surface N-doped carbon layer. On the other hand, the mesoporous structure of T-Nb 2 O 5 @N–C ensures fast Li + diffusion dynamics and electrolyte penetration. Furthermore, T-Nb 2 O 5 @N–C also performs well in a LiNi 0.5 Mn 0.3 Co 0.2 O 4 ||T-Nb 2 O 5 @N–C full cell. This work provides a facile method to construct integrated anode materials for potential applications in lithium-ion batteries. Graphical abstract